Researchers tested 20 websites and 33 apps designed to help predict
what’s known as the fertile window, the days before ovulation when
having sex is most likely to result in conception.
Typically, a woman with a standard 28-day menstrual cycle will
ovulate around day 15, which would also be the last day of a six-day
When researchers asked these apps and websites to give a fertile
window for a woman with a 28-day cycle, most of them reliably
predicted the day of ovulation, the study found. But only four
provided the correct fertile window.
“Before using any website or app, women need to understand that the
actual fertile window consists of the day of ovulation plus the
preceding five cycle days,” said lead study author Dr. Robert Setton,
a researcher at Weill Cornell Medicine and New York Presbyterian
“They can use the app or website to help them predict their
ovulation date and then use that as a guide for the rest of the
fertile window,” Setton added by email.
Setton and colleagues tested all of the websites and apps with the
same case: a woman with a 28-day menstrual cycle and four days of
menses whose last period started January 1.
In this test case, 80 percent of websites and 87 percent of apps
that predicted the day of ovulation correctly said it would occur on
January 15, the study found.
But just one website and three apps correctly predicted a fertile
window of January 10-15.
The only accurate website for the fertile window was babymed.com,
Setton said. Among the apps, the ones that got it right were iPeriod,
My Days and Clue.
The findings suggest that women should be cautious about relying
only on websites and apps to predict the best days each month to try
to conceive, the authors conclude in Obstetrics and Gynecology.
Couples using an incorrect fertile window from an app or website to
time intercourse may end up having sex too soon or too late in the
month to conceive, the authors note.
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One limitation of the study is that researchers only included free
apps and websites, the authors acknowledge. The study also didn’t
examine how often couples decide to have sex based on the fertile
window suggested by these tools, or explore how often couples
Even so, the findings suggest that women may want to rely on
alternatives to determine their fertile window each month, said
Deborah Lupton, a researcher at the University of Canberra in
Australia who wasn’t involved in the study.
Women can do this by tracking some changes in their bodies that
occur around ovulation, including a slight spike in body temperature
and an increase in vaginal discharge as the cervix releases thin,
“Once women do this for a while, they should get a good sense of
where in their cycle they ovulate,” Lupton said by email.
“These apps and software tools are not likely to be effective for
women who either are trying to conceive or using these tools to
avoid conception,” Lupton added.
SOURCE: http://bit.ly/1sxjq1H Obstetrics and Gynecology, online June
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